Electrically conductive optical element



SEARCH ROOM S. ZAROMB A ril 16, 1968 ELECTRICALLY CONDUCTIVE OPTiCALELEMENT Filed March 30, 1966 IiZ a F G /(a) FIG] Fla.

FIG.2(a/) Fla] FIG. 2(bl) F/G.2(b)

FIG. 2(dl) INV ENTOR. SOLOMON ZAROMB F/G.2(d)

ATTORNEY United States Patent 3,378,327 ELECTRICALLY CONDUCTIVE OPTICALELEMENT Solomon Zaromb, 376 Monroe St., Passaic, NJ. 07055Continuation-impart of application Ser. No. 305,161, Aug. 28, 1963. Thisapplication Mar. 30, 1966, Ser.

4 Claims. (Cl. 350-319) ABSTRACT OF THE DISCLOSURE An optical elementcomprises a transparent electrically conductive coating on a lightpermeable substrate, said coating being broken up by one or morenon-conductive longitudinal openings which are rendered inconspicuous byobturation with a transparent material of low electrical conductivitydirectly contacting said substrate and having substantially the samerefractive index as the conductive coating. The obturating and theconductive coating materials may be two differently doped forms of tinoxide. The obturating low conductivity material may be either in theform of a continuous layer beneath the conductive coating or may merelyfill the openings in the conductive coating.

This invention 'relates to methods and apparatus for generatingnon-conductive line patterns in electrically conductive surfaces orcoatings. This application is a continuation-in-part of my previouslyfiled application Ser. No. 305,161 of Aug. 28, 1963, issued as PatentNumber 3,305,666.

' In another previously filed and copending'application Ser. No. 257,988filed Feb. 12, 1963, issued as Patent Number 3,291,551, I have discloseda novel optical shutter in which strips of light-permeable conductivematerial are positioned on a light-permeable base and the strips arepositioned in an electrolyte so that an electrolytic deposition can beeffected to render the aforesaid strips selectively opaque therebyconstituting an optical shutter.

I now propose to make precise fine line patterns through a conductivecoating deposited on a light-permeable base with techniques which areadapted to mass production and to make such patterns invisible.

In accordance with the invention I propose to remove precise patternsfrom coatings applied to a light-permeable base, in combinationtherewith, to employ techniques which render the patterns invisible.

It is an object of the invention to provide improved methods fortreating conductive coatings in such a manner as to establish veryprecise non-conductive patterns therein.

Another object of the invention is to provide optically uniform shuttersfree of diffuse optical distortions which might arise due to differencesin transmission between conductive and non-conductve areas.

The methods of the invention as well as objects, features and advantagesof the invention will be better understood from the following detaileddescription of some of its preferred embodiments as illustrated in theaccompanying drawing in which: 3

FIGURE 1 diagrammatically illustrates a technique for effectivelyconcealing openings in the conductive coats;

FIGURE 1(a) is a cross-section taken along line Ia--Ia of FIG. 1; and

FIGURES 2(a)-2(d) and the corresponding crosssectional views of FIGS.2(a1)-2(d1) shows a further technique for concealing such openings.

With respect to the environmental background of the invention, I havepreviously proposed using a tin oxide coating on the surface of alight-permeable base such as glass, quartz and the like in associationwith an electrolyte and in such a manner that an electrical potential isapplied to the coating to cause an electrolytic deposition thereonwhereby the coating which is normally lightpermeable is caused to becomeopaque. This process is reversible and I have found that apparatus ofthis type functions very well as an optical shutter device.

The openings which have been noted above constitute non-conductive linesuseful in shutters and other electrical components of the above notedtype. An object of this invention is to provide optically uniformshutters free of optical distortions which might :arise due todifferences in light transmission between the conductive andnonconductive areas.

Generally, in accordance with the invention, the nonconductive areas maybe covered with a non-conductive material of the same or approximatelythe same refractive index as that of the conductive material. Inparticular, tin oxide may be provided in both conductive andnon-conductive forms depending on the doping or additives employed.Small concentrations of antimony make the tin oxide more conductivewhereas the addition of indium reduces the conductivity of a tin oxidefilm. Accordingly, it is proposed, in accordance with the invention, toobturate the windows or openings in the conductive coating of tin oxidewith non-conductive tin oxide. The two forms of tin oxides haveapproximately the same refractive index. Because tin oxide isessentially trans parent, it is only because of the differences ofrefractive index as between tin oxide and the transparent supportingbody of glass, quartz or the like which renders the openings or windowsvisible. The refractive index of tin oxide is approximately 2.0 and thatof, for example, a glass supporting body may be approximately 1.5. Bycovering or obturating the openings with the non-conductive tin oxidethe openings are at least substantially completely masked.

While non-conductive or poorly conductive tin oxide must constitute thepreferred masking material because of its close similarity to theconductive tin-oxide coating,

other substances whose refractive index is closer to that of tin-oxidethan to that of glass could obviously serve the same purpose, althoughnot as well as the non-conductive tin oxide coating.

Two processes accomplishing the above are illustrated in the drawing.More particularly, in FIGS. 1 and 1(a) appears a transparent supportingbody 74 and on this body is deposited a complete coating ofnon-conductive transparent material 76 constituted, for example, by theaforesaid non-conductive tin oxide. Thereafter, a coating of conductiveoxide film 78 is deposited on material 76 and finally, openings 80 areformed in the uppermost layer only by the use of one of the techniquesdescribed hereinbefore. The openings 80 thus do not connect directlywith body are matched.

Alternative to the above, openings 82 (FIGS. 2(a) and 2(al) may be madein conductive coating 84, thereby exposing transparent supporting body86. As then appears in FIGS. 2(b) and 2(b1), the conductive coating canbe plated with a platinum mask 88 or the like whereby openings 82 willstill remain. As appears in FIGS. 2(a) and 2(c1), openings 82 are nextcoated with non-conductive tin oxide 90 or other suitable material andthe depositing of this materialneed not be effected with any finesseinasmuch as appears in FIGS. 2(d) and 2(d1) the platinum film is removedwith aqua regia or by mechanical peeling or the like to expose theconductive oxide coating 74 and, as a result, the refractive indexesPatented Apr. 16, 1968 surrounding the windows which are now obturatedwith non-conductive material.

There will be obvious to those skilled in the art, many modificationsand variations of the methods and optic-a1 elements set forth above.These modifications and variations will not depart from thescope of theinvention it defined by the following claims.

What is claimed is:

-1. A light shutter element comprising a light-permeable substrate, acoating of transparent electrically conductive material on saidsubstrate and broken up by at least one longitudinal opening, and atransparent material of low electrical conductivity o-bturating a majorportion of said opening and directly contacting said substrate so as torender said major portion substantially inconspicuous, the two saidmaterials having substantially the same refractive index.

2. A shutter element as claimed in claim 1 wherein both materials aretwo forms of tin oxide.

3. A shutter element as claimed in claim 1 wherein the low conductivitymaterial is in the form of a continuous layer beneath said coating.

4. A shutter element as claimed in claim 1 wherein the longitudinalopening is filled with said 10w conductivity material.

References Cited UNITED STATES PATENTS Colbert et al. 219-543 X Lyon219-543 X Thomson et al. 338-292 Gaiser 219-522 X Linder 219-543 Davis219-543 X Davis v 338-308 Browne 338-309 X Eisler 219-549 X Flanagan eta1. 88-61 Plumat 219-543 Griest et al. 338-309 Marks 88-61 Balde et al.338-308 Griffin et al 219-50 Cox 219-383 X Pratt 219-384 RICHARD M.WOOD, Primary Examiner.

VOLODYMYR Y. MAYEWSKY, Examiner.

